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Diffstat (limited to 'include/asm-x86/percpu.h')
-rw-r--r--include/asm-x86/percpu.h72
1 files changed, 72 insertions, 0 deletions
diff --git a/include/asm-x86/percpu.h b/include/asm-x86/percpu.h
index 736fc3bb8e1..4e91ee1e37a 100644
--- a/include/asm-x86/percpu.h
+++ b/include/asm-x86/percpu.h
@@ -22,6 +22,32 @@
DECLARE_PER_CPU(struct x8664_pda, pda);
+/*
+ * These are supposed to be implemented as a single instruction which
+ * operates on the per-cpu data base segment. x86-64 doesn't have
+ * that yet, so this is a fairly inefficient workaround for the
+ * meantime. The single instruction is atomic with respect to
+ * preemption and interrupts, so we need to explicitly disable
+ * interrupts here to achieve the same effect. However, because it
+ * can be used from within interrupt-disable/enable, we can't actually
+ * disable interrupts; disabling preemption is enough.
+ */
+#define x86_read_percpu(var) \
+ ({ \
+ typeof(per_cpu_var(var)) __tmp; \
+ preempt_disable(); \
+ __tmp = __get_cpu_var(var); \
+ preempt_enable(); \
+ __tmp; \
+ })
+
+#define x86_write_percpu(var, val) \
+ do { \
+ preempt_disable(); \
+ __get_cpu_var(var) = (val); \
+ preempt_enable(); \
+ } while(0)
+
#else /* CONFIG_X86_64 */
#ifdef __ASSEMBLY__
@@ -143,4 +169,50 @@ do { \
#define x86_or_percpu(var, val) percpu_to_op("or", per_cpu__##var, val)
#endif /* !__ASSEMBLY__ */
#endif /* !CONFIG_X86_64 */
+
+#ifdef CONFIG_SMP
+
+/*
+ * Define the "EARLY_PER_CPU" macros. These are used for some per_cpu
+ * variables that are initialized and accessed before there are per_cpu
+ * areas allocated.
+ */
+
+#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
+ DEFINE_PER_CPU(_type, _name) = _initvalue; \
+ __typeof__(_type) _name##_early_map[NR_CPUS] __initdata = \
+ { [0 ... NR_CPUS-1] = _initvalue }; \
+ __typeof__(_type) *_name##_early_ptr = _name##_early_map
+
+#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
+ EXPORT_PER_CPU_SYMBOL(_name)
+
+#define DECLARE_EARLY_PER_CPU(_type, _name) \
+ DECLARE_PER_CPU(_type, _name); \
+ extern __typeof__(_type) *_name##_early_ptr; \
+ extern __typeof__(_type) _name##_early_map[]
+
+#define early_per_cpu_ptr(_name) (_name##_early_ptr)
+#define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
+#define early_per_cpu(_name, _cpu) \
+ (early_per_cpu_ptr(_name) ? \
+ early_per_cpu_ptr(_name)[_cpu] : \
+ per_cpu(_name, _cpu))
+
+#else /* !CONFIG_SMP */
+#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
+ DEFINE_PER_CPU(_type, _name) = _initvalue
+
+#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
+ EXPORT_PER_CPU_SYMBOL(_name)
+
+#define DECLARE_EARLY_PER_CPU(_type, _name) \
+ DECLARE_PER_CPU(_type, _name)
+
+#define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
+#define early_per_cpu_ptr(_name) NULL
+/* no early_per_cpu_map() */
+
+#endif /* !CONFIG_SMP */
+
#endif /* _ASM_X86_PERCPU_H_ */